exhaust what do you think?

Discussion in 'Motorized Bicycle General Discussion' started by Russell, Feb 9, 2010.

  1. Russell

    Russell Active Member

    Joined:
    Apr 19, 2009
    Messages:
    1,187
    Likes Received:
    8
    I have a tuned pipe, great power but too noisy. Am going to leave that bike alone.
    The other bike has pretty much a standard exhaust. Today I replaced it with a larger tube & matched port. On the end of the tube I have two standaed HT mufflers IN PARRALLEL NOT IN SERIES. My thinking is that back pressure will be reduced but noise will not increase. Won't get to try it till the snow goes, what do you think the effect will be?
     

    Attached Files:

    #1 Russell, Feb 9, 2010
    Last edited: Feb 10, 2010
  2. john_the_great

    john_the_great New Member

    Joined:
    Oct 24, 2009
    Messages:
    191
    Likes Received:
    0
    I think you will lose a tiny bit of torque on the bottom end of the rev range and gain a little more rev on the top end(if the carb can keep up)
     
  3. Venice Motor Bikes

    Venice Motor Bikes Custom Builder / Dealer/Los Angeles

    Joined:
    Mar 20, 2008
    Messages:
    6,169
    Likes Received:
    18
    I think it will greatly improve all across the board!! ;)
     
  4. Russell

    Russell Active Member

    Joined:
    Apr 19, 2009
    Messages:
    1,187
    Likes Received:
    8
    Pic' of exhaust pipe.
     

    Attached Files:

  5. PaulFlorida

    PaulFlorida New Member

    Joined:
    Dec 4, 2009
    Messages:
    52
    Likes Received:
    0
    Honda did that on the CRF250. Just as loud, twice as heavy. It'll breath better for sure.
     
  6. mekano

    mekano New Member

    Joined:
    Nov 4, 2008
    Messages:
    219
    Likes Received:
    0
    Better than standard exhaust for sure.
     
  7. Venice Motor Bikes

    Venice Motor Bikes Custom Builder / Dealer/Los Angeles

    Joined:
    Mar 20, 2008
    Messages:
    6,169
    Likes Received:
    18
    The main problem with the stock pipes is that they are quiet enough, but they are very restrictive!!! Having two of them should be just as quiet & have a much better flow! (which means more power!! ;) )
     
  8. the new ausped

    the new ausped New Member

    Joined:
    Feb 10, 2010
    Messages:
    144
    Likes Received:
    0
    I THINK THAT I YOU PPUT UR FINGR OVER THE TOP ONE IN THE FIRST PIC IT WO T MAKE any diference
     
  9. BarelyAWake

    BarelyAWake New Member

    Joined:
    Jul 21, 2009
    Messages:
    7,209
    Likes Received:
    4
    I think that as the outlet on a stock can is less than 1/2 the size of the inlet - havin' two will reduce restriction o_O
     
  10. warner

    warner New Member

    Joined:
    Jun 5, 2008
    Messages:
    60
    Likes Received:
    0
    IF the single muffler was restrictive, then some of the exhaust gasses will look for the path of lesser resistance and flow through the top muffler which will give you a bit more top end (again assuming that the exhaust was a bottleneck for "breathing").

    I don't think it will be any quieter, COULD end up being louder. I don't expect you'd lose ANY low end torque....unless the single muffer was SO restrictive that it wasn't flowing enough even at low revs.

    Two stroke exhausts are SO important to how the engine operates (eg - backpressure, scavenging, harmonics....), that just about anything can happen when you start messing with pipe lengths and mufflers, etc...

    Give it a try and post your results back here....should be an interesting experiment!


    Warner
     
  11. Russell

    Russell Active Member

    Joined:
    Apr 19, 2009
    Messages:
    1,187
    Likes Received:
    8
    Ausped,
    You could be right, however the exhaust pipe was also increased in dia. and match ported. I am going with the general response that there will some increase in power overall(nowhere near the increase you would get with a tuned pipe). I have a tuned pipe on one bike but doubt that the neighbors enjoy it as much as I do!
    So what I am hoping for is a middle ground. There is going to be a cold weather tri state rally from Ma.to Nh. to Maine next week so I will be firing it up. Will post the results be it good/bad or no change! Still it has been a fun experiment.
     

    Attached Files:

    #11 Russell, Feb 11, 2010
    Last edited: Feb 11, 2010
  12. K.i.p

    K.i.p New Member

    Joined:
    Nov 8, 2009
    Messages:
    340
    Likes Received:
    0
    Total unprofessional speculation here, but, it would seem the exhaust gases and associated sound waves now have two avenues of escape. Neither muffler will be under the same pressure or work load of a single stock muffler. My guess would be a decrease in emitted sound waves. Also as previously noted with two exits available the back pressure should be decreased roughly two fold. It would be out of my range of knowledge to speculate on performance changes. I too am very curious about your results.
     
  13. Russell

    Russell Active Member

    Joined:
    Apr 19, 2009
    Messages:
    1,187
    Likes Received:
    8
    The good part of this is, once it is driven for a while and I believe that their is a differance. It is easy to plug one muffler and see if it was just the larger dia. exhaust pipe or the mufflers. the next test would be to alternate pluging the mufflers and see if their is a differance between them.
     
  14. the new ausped

    the new ausped New Member

    Joined:
    Feb 10, 2010
    Messages:
    144
    Likes Received:
    0
    what i was trying to get across is that fumes of any sort will never turn a corner willingly that pipe on the side will act more as a pressure relese
     
  15. Russell

    Russell Active Member

    Joined:
    Apr 19, 2009
    Messages:
    1,187
    Likes Received:
    8
    Ausped,
    I HVAC systems, sometimes a small scoop is extended into the main trunk line for a branch(robber) for just that reason. However who knows if in this setup if it would help or hurt. Both mufflers are used, no idea which has the most restriction. I am totaly in agreement with the principal.
     
  16. Russell

    Russell Active Member

    Joined:
    Apr 19, 2009
    Messages:
    1,187
    Likes Received:
    8
    Well, fueled it up and took her for a spin. Cold out 33 Deg. Motor started right up(pull start). Let it warm up and off me and my new muffler system went. No need pedel, there was an increase in low end tourque. The most noticable change was the sound, much diffrent! It has a much lower sound and pitch, unlike the normal 2 cycle sound. I would guess that the tourque increase is between 5-11%. I do not yet know if this tourque increase is due to the mufflers as it now has a larger port matched exhaust pipe.
    I do know the sound change is the mufflers and I would have been happy with just that.
    I spent most of the time checking out the bike itself preparing for mondays tri-state run.
    This motor does not however have the power that my tuned pipe motor does. I feel the small effort was worth it.
    Thanks all for your input.

    Russ
     
    #16 Russell, Feb 12, 2010
    Last edited: Feb 14, 2010
  17. adam

    adam New Member

    Joined:
    Feb 13, 2010
    Messages:
    3
    Likes Received:
    0
    my end cap fell off the exhaust pipe.who sells the end cap only?
     
  18. mikldom

    mikldom New Member

    Joined:
    Jan 4, 2010
    Messages:
    33
    Likes Received:
    0
    I like the Panniers.. How'd you do those?

    You are full of so many ideas.

    I am picking up and XL OCC next week, and I have decided that is going to be the new project OCC, and have the other 5 as backups.

    I am thinking of stripping one of them down and getting it powder coated pink for the wife as she is into that kinda stuff (all pink crap).
     
  19. Dave31

    Dave31 Moderator
    Staff Member

    Joined:
    Mar 1, 2008
    Messages:
    11,207
    Likes Received:
    13
    Hey adam, welcome to the forum my fellow Arizonanan.

    As far as I know nobody just sells the end cap, most just make one.

    Hmmmm, I know we have some threads about making them, I will post them as soon as I find um.
     
  20. Tad Bit Tipsy

    Tad Bit Tipsy New Member

    Joined:
    Jan 2, 2010
    Messages:
    478
    Likes Received:
    0
    Hey Russell,
    If my eye do not deceive me...
    Love that Tennis Ball seat adjuster!!!
    Had one of those on my low rider to keep my big keester up, ha ha.
     

Share This Page